Meg is the abbreviation of mono ethylene glycol, and its Chinese name is Monoethylene Glycol.

Ethylene glycol, also known as "ethylene glycol" and "1, 2- ethylene glycol", is abbreviated as EG, and its chemical formula is (CH2OH)2, which is the simplest diol. Ethylene glycol is a colorless and odorless sweet liquid, which is toxic to animals. The lethal dose to human is about 1.6 g/kg. Ethylene glycol is soluble in water and acetone, but insoluble in ether. Used as solvent, antifreeze and raw material for synthetic polyester. Polyethylene glycol (PEG) is a polymer of ethylene glycol, a phase transfer catalyst and also used for cell fusion. Its nitrate ester is an explosive.

MEG is the abbreviation of mono ethylene glycol, and its Chinese name is Monoethylene Glycol. Its structure is that both ends of ethyl group are connected with a hydroxyl group. It is the simplest diol. It undergoes continuous polycondensation with PTA to synthesize PET, which is mainly used as chemical fiber (polyester).